My goal in applying for this award is to obtain the additional training I need to develop an independent program of research focused on developing and testing theory-based strategies to increase participation in preventive parenting programs among low-SES, inner-city parents of young children. Parenting skills interventions have proven to be helpful in preventing the onset and escalation of child mental health and substance use disorders. However, engagement rates in parenting interventions are often quite low, severely limiting their impact at the population level. Although efficacy and participation rate contribute equally to population effectiveness, an abundance of research has been devoted to the former with little empirical study of the latter. NIMH has identified research examining determinants of mental health service participation and formulating and testing strategies to enhance engagement, retention, and intervention adherence as primary research objectives (NIMH, 2000, 2001 a, 2001 b). Thus, maximizing participation may be one of the most important enterprises prevention scientists can undertake to increase the public health benefits of parenting interventions. To attain my career goals, I will need to develop skills in four areas: 1) developing and evaluating theory-based strategies for increasing parent participation; 2) knowledge of theory and research that inform the study of participation; 3) culturally-competent measurement and intervention development; and 4) advanced statistical methods for prevention research. Two studies will be conducted as part of the research plan. The objectives of the first study are to obtain feedback from 40 parents on the acceptability and perceived effectiveness of an engagement intervention designed to increase participation in preventive parenting programs. In Study 2, the engagement intervention will be piloted with 228 parents to test its efficacy for increasing parent participation. Study 2 will also expand on previous research to include consideration of how participation is influenced by motivational factors, parenting cognitions, parental adjustment, program preferences, and sociocultural factors. Increasing participation in evidence-based parenting interventions will improve the public health impact of these interventions by increasing the number of families who receive services, thereby decreasing population-level rates of child mental health and substance abuse disorders.